This computer is connected to a Sharp Aquous TV using HDMI. It all worked fine with Windows 7 64 bit.

In Device Manager I see GeForce 9400 and have installed the latest NVidia drivers (295.73 WHQL).

However, when I click on the change the screen resolution to 1920x1080, I see that Windows 8 thinks that it's using some other graphics card with Microsoft Basic Display Driver. This was made clear, when I tried to launch the NVidia tools and it claimed that the current monitor (in this case my TV) wasn't attached to the GeForce 9400 card.

In Device Manager, there's a "Coprocessor" and "Unknown device" without drivers, but I've no idea what they are. I've run the original CD that the motherboard came with no success.